1. Field of the Invention
The present invention relates to a differential assembly that is lubricated to prevent excessive heat buildup. More specifically the present invention relates to an apparatus that removes heat from the axle assembly or torque transmission device.
2. Description of Related Art
Typically axles are lubricated by a reservoir of oil in the sump which is circulated by the moving components. This is known as splash lubrication. The operating temperature of a splash lubricated axle assembly or other torque transmission device is generally dependent on the torque being transmitted, the ambient temperature, the speed of rotation and airflow over the device.
The operating temperature can be just above the ambient temperature to more than 200 degrees F above ambient. Operating temperatures significantly above 250 degrees F can begin to cause problems with the durability of the components in the axle as well as the lubricant itself. These temperatures are generally encountered at higher speeds and/or torques such as high speed highway driving or trailer towing. Therefore it is desirable to avoid these higher temperatures as much as possible. It is the intention of the present invention to minimize these high operating temperatures.
It is known to provide cooling conduits within an axle assembly in order to avoid high operating temperatures. These conduits are positioned about a majority of the differential assembly and contain a hydraulic fluid from another device which is capable of cooling the lubricant in the axle.
It is also known to have a differential assembly with a heat pipe having heat absorbing portions extending through an oil sump as well as externally disposed heat transmitting devices.
Additionally, it is know to have a heat pipe including a closed tube having a heat exchange medium comprised of a plurality of fins.
Thus, the aim underlying the present invention lies in providing an effective fluid lubricant cooling area that is readily utilizable, without significantly increasing the costs of production, the required space, and weight.
It is therefore an object of the present invention to provide temperature regulating apparatus for a differential assembly. The present invention will provide a cooling mechanism for a differential assembly through a heat pipe having cooling fins disposed thereon. One of the heat pipes is inserted through the carrier cover and is situated within the lubricating fluid reservoir in the bottom of the carrier. The heat pipe assembly extends horizontally through an axle lubricant, the heat pipe extends in a vertical direction within the differential carrier then passes from an interior of the carrier to an external ambient environment, the heat pipe extends along an axle tube projecting from the carrier.
Another heat pipe is inserted into the differential assembly via the pinion extension. Cooling fins are situated on the terminal end of the heat pipe section situated outside the pinion assembly.
The present invention provides a cooling means for fluid splashed within the differential assembly or other similar torque transmission device in order to reduce or eliminate higher portion of the normal operating temperature range to maximize efficiency.
The advantageous features of the present invention include cooling of lubricating fluid through use of at least one heat pipe with a heat absorbing portion of the heat pipe exposed to the lubricating fluid and the heat transmitting element exposed to the external environment. The cooling fins inside an axle assembly are designed to absorb heat generated while the cooling fins located in the external environment dissipate the same heat in order to cool the entire assembly.
These advantages and other novel features of the present invention will become apparent in the following detailed description of the invention when considered in conjunction with the accompanying drawings.